Hydrocarbon oil compositions containing telomeric polyalkyl oxoesters as anti-foaming agents



Patented Sept. 29, 1953 HYDROCARBON on, COMPOSITIONS CON- TAINING.TELOMERIC ,POLYALKYL X0 ESTERS AS ANTI-FOAMING AGENTS Joseph Fields andTracy Patrick; .1 Dayton, Ohio, assignors to Monsanto" Chemical Company;StaLi'niis, Mo., a: corporation of Dela ware 1% Drawing. paiafios m m 1,1952',

SerialNo. 269,602 1'2 Glaiiiiis. (Cl; 252-56)" This invention relatestoantifoaming hydrocarbon oils and deals more particularly withhydrocarbon oils containing small" amounts of liouidtelomeric polyalkyloXoestersl The problem of foam inhibition is one"of ma= jor importanceto all industries employing Hydrocarbon oils under foam-inducingconditions;- While most oils wil1 foam to some extent" due to vigorousagitation and aeration in arunningengine, foaming becomes a problemonlywhen loss of oil occurs by foam seepage or" when'so many air bubbles arepresent in the oil that proper lubrication of bearing surfacesisimpeded.Foaming is often experiencedwith drysurnp" engines in which there isemployed a'scave'nger pump for collecting oil from various engine parts"and returning it to the lubricant reservoir. Here air may be collectedalongwiththe oil and deposited in the reservoir. The design and operation of aircraft engines issucli" that foaming 0c curs more readily inthis type-of engine thanit does in automotive engines.

Foam and froth in hydrocarbon oils, however;- is not due solely toengine-design. Although-loca tion and design of the oil pump, oil suinpand oil lines as well'as modification of other engineering features: mayretard foam'develop ment, "when certain oils are employed with high;speed engines, mechanical" control, alone, does not suffice. Here, thenature of the crank 'case oil is often the prime factor in roaming diificulties. Theheavier the gradeof the oil' o'r' th'e higher the viscosityof the oil, the more dif ficult it is to avoidfoaming. Heavy gradeoils;such as those employed in' high-speed di'es'el and spark ignitionengines operating under severe conditions are particularly susceptibleto foa'rn ing. The heav oils hold bubbles very firmly-so that when foamis formed, it is very persistent;

New developments in engine constructionhave" constantly demandedlubricants'havihg proper-'- ties not possessed by crude hydrocarbonoils.- Such properties are'nowgener'ally conferredto lubricants by theuse of additives; For eii'arh ple, in order to satisfy the lubricationrequire: ments of hypoidgears, materials, whichim expense of increasingits susceptibility to foam;

Thus, while-the demandsof modern engine'*de-- sign for extreme pressureresisting lubricants;

for anticorrosive lubricants, for lubricantsof'iIf: creased viscosityand 'low" pour-point andgfoo'df detersive properties have" been met bytheior' 2. inulation' and use of numerous chemicals which give thesedesirable properties to oils when adniixedtherewith, the use of suchadditives makes the treated oils particularly susceptible to foaming.While light grade oils, e. g., SAE 10 grade oils are almost non-foamingunder the most severe conditions, when there are employed with theseoils one or more additives such as viscosity index improver's, extremepressure resisting improver's','pour'-point depressors, etc, the resultimproved oil's do notretain their nonreamin chalracteristics and arefrequently even nioresusceptibleto foaming than are the heavy del 4 I-Ience, with thedevelopmer'it-of new high-speed engines and the provision"of the new additivetyp'e-lubricants', the problem of foaming has assumedmajor importance; Attempts to solve the problem by defoaming ensuingo'il's, e. g., by submitting oils to" heat treatment, absorptionprocessesyfilteringlstep's, etch,- have proved of but little value, Themost practical solution to this problem has-been made by the use ofantifoam additives. j V

.A number of'antifoani additives, i. e., antifoaming' agents} roamdepressing agents, foam depressants; antifrotlierspr foamsup'pressorsarc known; but in prior art their use has been attended'with numerous difficulties. Among disadvantages'ofsuch known additivesare chemical reactvity with' the'lubricant or other oiladdieves;massive-eases susceptibility to decomposi tion upon-' 'h'eatinginstability when exposed for long-period'sof time toordinary'atmospheric conditions, high co'stfetc.

Now we hav'e round' that foaming of hydrocarbon oils is:efficiently'retarded and even completelyinhibited' when-there is addedto such oils' a sr'nall quantity, say; from 0.001 per cent to 1.0percent by" v'vig'ht of a liquid mixture of t'eldrn'ersprepar'edbyreactionof onevmole of a saturated, alirilria'tic aldehyde of from 2to 13 carbon atomsfwith n'iore than' one mole of certain esters ofm-unsaturated aliphatic, dicarbokylicacids. Teloiners of this kind aredescribed inthe copending application of Tracy M; Fatrick, Jr .'and EarlW. Gluesenkamp, Serial'No. 200,101, fi e peeember' 9; 1950; They arereadil obtained by a free radicalcat'alyzed addition re in which R. isan alkyl radical of from 1 to 12 carbon atoms, X is selected from theclass consisting of hydrogen and the methyl radical and R and R" areselected from the class consisting of alkyl, cycloalkyl, aryl, alkaryland aralkyl radicals of from 1 to 18 carbon atoms and n is an integergreater than one.

Saturated aldehydes which may be employed for the preparation of thepresent adducts are, ifor example, acetaldehyde, propionaldehyde,nbutyraldehyde, isobutyraldehyde, n-valeraldehyde, isovaleraldehyde,methylethylacetaldehyde, trimethylacetaldehyde, n-caproic aldehyde,isohexaldehyde, Z-ethylhexaldehyde, octaldehyde, capric aldehyde,undecaldehyde, lauric aldehyde, palmitic aldehyde, stearic aldehyde,etc. Esters which react with the above aldehydes to yield telomers whichare useful for the present purpose are, for example, dimeth'yl, diethyl,diisopropyl, di-n-butyl, bis(2-ethylhexyl), dicyclohexyl, dibenzyl,di-p-tolyl, dihexadecyl, and didodecyl maleate; dimethyl, diisobutyl,dioctadecyl, diphenyl and dicyclopentyl fumarate, dipropyl, dioctlyl,bis(2-phenylethyl) and di-a-naphthyl citraconate, dimethyl, diundecyl,dixenyl and dibenzyl mesaconate, etc.

The liquid telomeric polyalkyl oxoesters are effective antifoamingagents when they are employed in very low proportions, i. e., in amountsof up to 1.0 per cent by weight, based on the weight of the totalhydrocarbon oil composition. From .01 per cent to .10 per cent of thetelomeric esters is preferred, depending upon the nature of the oil.Heavy oils and oils containing foaminducing adjuvants require more ofthe present antifoaming adducts than do base oils of good viscositycharacteristics.

Particularly valuable as antifoaming additives for hydrocarbon oils areliquid telomeric polyalkyl oxoesters in which one mole of a saturated,unsubstituted aliphatic aldehyde of from 2 to 12 carbon atoms hascombined with from 2 to 30 moles of an ester selected from the classconsisting of dialkyl and dicycloalkyl maleates, fumarates, mesaconatesand citraconates in which each alkyl radical and each cycloalkyl radicalhas from 1 to 12 carbon atoms. The dialkyl and di cycloalkyl maleates inwhich each alkyl radical has from 1 to 8 carbon atoms are commerciallyavailable, inexpensive starting materials, and telomers prepared fromsuch maleates are the preferred antifoaming agents at present.

The antifoaming effect of the aldehyde-ester telomers is not materiallyafiected by the presence of other adjuvants in the oil. The liquidtelomers are stable polyesters which can be hydrolyzed only withdifficulty, and since they are present in the oils in only very smallquantities, the use of even very acidic or very basic additions in theoil has substantially no effect on the telomers. Hydrocarbon oilscontaining the present antifoaming agents are stable when stored overlong periods of time and also when subjected to heat and pressureconditions of engine and motor operation.

While the antifoaming effect of the liquid telomers is obtained whenthey are employed in concentrations of up to 1.0 per cent by weight,they may be incorporated into hydrocarbon oils in much higherproportions, e. g., in amounts of up to 10 per cent or even 50 per centof the weight of the hydrocarbon oil to give concentrates. Oilscontaining such high proportions of the telomers may be manufactured andsold for use as lubricant additives. Addition of small amounts of suchconcentrates to hydrocarbon oils may be made so as to supply an oilcontaining suitable quantities of the telomers.

Hydrocarbon oils which are rendered substantially antifoaming byincorporation therein of quantities of up to 1.0 per cent of the presenttelomeric oxoesters are synthetic or petroleum stocks of varyingviscosities such as lubricating oils for internal combustion engines andmotors, diesel fuels and lubricants and pressure transfer media, e. g.,industrial lubricants, process oils, hydraulic oils, turbine oils,cutting oils, fluid greases, gear oils, shock absorber oils, spindleoils, journal bearing oils, pneumatic tool lubricants, etc. They may besynthetic or natural hydrocarbons of any type, i. e., parafiinic,naphthenic or blended.

The invention is further illustrated, but not limited, by the followingexample.

Example The antifoaming properties of lubricants may be determinedaccording to the procedure generally described in Designation L-l2-445of the Coordinating Lubricants Research Committee of the CoordinatingResearch Council, New York. Briefly this procedure involves bubbling airor an inert gas such as nitrogen through the hydrocarbon oil to betested, employing standard apparatus and standard conditions.

Theoil was placed in a standard IOU-ml. graduated cylinder in the top ofwhich was inserted a two-hole rubber stopper. An air-inlet tube extendedthrough this stopper, to the bottom of which was attached a gas diffuseror porous stone sphere. The length of the inlet tube was adjusted sothat when the apparatus was as 'sembled, the sphere just touched thebottom of the cylinder. The sphere was attached to the inlet tube bymeans of litharge or glycerine, or by a copper tube soldered to thedifiuser-stone coupling. The oil bath used was capable of controllingtemperature at 200i1 F. (93.3:0.6

' 0.), large enough to permit the cylinder to be immersed at least tothe ml. mark, and arranged to permit the visual observation of thegraduations 0n the cylinder.

Dr nitrogen or air was supplied at the rate of 0.2 cubic foot per hour,employing a calibrated flowrneter. The sample was heated to F. (48.9"0.), and then cooled, before testing, to 75i5 F. (23.9i2.8 C.) in aconstant temperature room. 25 cc. of oil was used for each test.

With the air hose disconnected between the fiowmeter and the deliverytube to the diffuser stone, the stone was allowed to soak in the oil for5 minutes, at the end of which time the air flow (0.2 cu, ft. per hour)was started through the stone. Zero time was noted when the air ornitrogen bubbles started to rise from the stone. Readings of the top andbottom foam levels were taken at the end of a 5-minute period. Thevolume of foam was calculated from the two readings.

Employing the testing procedure described above, there were determinedthe antifoaming effects of various aldehydemaleate telomers when addedto a Champlin 30 SAE base'oil in concentrations of from 0.05% to 005% byweight of the oil. The telomers were prepared by heating mixtures of thealdehyde and maleate indicated below in the presence of benzoyl peroxideas catalyst, and removing from the resulting reaction mixture anyunreacted material and 1:1 addition product by distilling the mixture upto B the head temperatures shown below, as described in the previouslycited copending application.

Reactants Used e B. P. of Telomer, l??? above Head Temp.

Aldehyde Maleate Of 1 Butyraldehyda. Dicyclohexyl. 185 O./l mm. 2 .dobi]sJ-2-(lil)th-yl- 184 C ./0.5 mm.

exy 3 Heptaldehyde .do 2102 GJOXZ 4 2 Ethylhexal- Diethyl 136 C./0.8 mm.

dehyde.

The following antifoaming values were obtained with these telomers:

Foam (cc.) in 5 Min. Additive in p. p. m; of-oil Additive, rrelome'r N0.

None. 500 200 so Nonfoaming hydrocarbon oil compositions are alsoobtained by incorporating into such oils in a quantity of up to 1.0 percent, based on the weight of the composition, telomers of othersaturated aliphatic aldehydes of from 2 to 13 carbon atoms and otherdicarboxylates having the general formula o o o R do on" in which X isselected from the class consisting of hydrogen and the methyl radicaland R and R" are selected from the class consisting of alkyl,cycloalkyl, aryl, alkaryl and aralkyl radicals of from 1 to 18 carbonatoms. Thus instead of the telomers tested above, there may beadvantageously employed, e. g., telomers of acetaldehyde and didodecylfumarate, propionaldehyde and dil-tolyl citraconate, n-valeraldehyde anddinaphthyl mesaconate, lauric aldehyde and dimethyl fumarate, etc. Thepresent telomers impart antifoaming properties to hydrocarbon oils,generally, in the presence or absence of other customarily employedadditives such as extremepressure resisting additives, detergentadditives, etc.

This is a continuation-in-part of our application Serial No. 217,324,filed March 23, 1951, now abandoned.

What we claim is:

1. A hydrocarbon oil composition containing up to 1.0 per cent byweight, based on the total composition, of a liquid telomeric polyalkyloxoester having the general formula R.CO CH 011- ]H JJOOR' 4700B" n inwhich R is an alkyl radical of from 1 to 12 carbon atoms, and R and R"are selected from the class consisting of alkyl, cycloalkyl, aryl,alkaryl and aralkyl radicals of from 1 to 18 carbon atoms and n is aninteger greater than one.

2. A hydrocarbon lubricant composition containing up to 1.0 per cent byweight, based on the total composition, of a liquid telomeric polyalkyloxoester having the general formula 11.00 -on-cn- 1H 00R coon" in whichR. is an alkyl radical of from 1 to 12 .6 carbon atoms, and R..andR""areselecte;d from the class consisting of alkyl, cycloalkyl,aryl, alkaryl and aralkyl radicals of from 1 to 18 carbon atoms and n isan integer greater than one.

3. A substantially antifoaming hydrocarbon lubricant compositioncontaining up to 1.0 per cent by weight, based on the total composition,of a liquid telomer having the formula CHa(CH2)a-CQ on OH ]H oooo ioooyin which Cy denotes the cyclohexyl radicalfland n is an integer greaterthan one.

4. A substantially antifoaming hydrocarbon lubricant compositioncontaining up to 1.0 per cent by Weight, based on the totalcompositiomo'f a liquid telomer having the formula CH- 11;. OOAlkc-ooalk in which Alk denotes the .2-ethylhexyl radical and n is anintegergreater than one.

5. A substantially .antifoaming hydrocarbon lubricant compositioncontaining up to 1.0 per cent by weight, based on the total composition,of a liquid telomer having the formula in which Alk denotes the2-ethylhexyl radical and n is greater than one.

6. A substantially antifoaming hydrocarbon lubricant compositioncontaining up to 1.0 per cent by weight, based on the total composition,of a liquid telomer having the formula in which Et denotes the ethylradical and n is an integer greater than one.

7. The method of imparting antifoaming propperties to hydrocarbon oilcompositions which comprises incorporating into said compositions up to1.0 per cent by weight, based on the total composition, of a liquidtelomeric polyalkyl oxoester having the general formula in which R is analkyl radical of from 1 to 12 carbon atoms, and R. and R." are selectedfrom the class consisting of alkyl, cycloalkyl, aryl, alkaryl andaralkyl radicals of from 1 to 18 carbon atoms and n is an integergreater than one.

9. The method of imparting antifoaming properties to hydrocarbonlubricant compositions which comprises incorporating into saidcompositions up to 1.0 per cent by weight, based on the totalcomposition, of a liquid telomer having the formula CHs(CHz)a.CO CH CH-1H JOOCy JJOOCY n in which by denotes the cycloalkyl radical and n is aninteger greater than one.

10. The method of imparting antifoaining properties to hydrocarbonlubricant compositions which comprises incorporating into saidcompositions up to 1.0 per cent by weight, based on the totalcomposition, of a liquid telomer having the formula ormcnmco OH CH H I:OOAlk dooAlkl .in which Alk denotes the 2-ethylhexy1 radical and n is aninteger greater than one.

11. The method of imparting antifoaming properties to hydrocarbonlubricant compositions which comprises incorporating into saidcompositions up to 1.0 per cent by weight, based on the totalcomposition, of a liquid telomer having the formula in which All;denotes the 2-ethylhexyl radical and n is an integer greater than one.

. 12. The method of imparting antifoami'ng properties to hydrocarbonlubricant compositions which comprises incorporating into saidcompositions up to 1.0 per cent by weight, based on the totalcomposition, of a liquid telomer having the formulaOHz(CHi)a?H.OHz.OO[OH-GH :lH

in whichEt denotes the ethyl radical and n is an integer greater thanone.

JOSEPH E. FIELDS. TRACY M. PATRICK, JR.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,417,833 Lincoln et a1. Mar. 25, 1947 2,430,858 Borsoff et a1Nov. 18, 1947 2,528,466 Borsofi' et a1 Oct. 31, 1950

1. A HYDROCARBON OIL COMPOSITON CONTAINING UP TO 1.0 PER CENT BY WEIGHT,BASED ON THE TOTAL COMPOSITION, OF A LIQUID TELOMERIC POLYALKYL OXOESTERHAVING THE GENERAL FORMULA